Current Conditions
Temp0.1 C
RH73 %
WindSW 5 mph
RoadOpen (4x4)
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Hawaiian Islands Synoptic Discussion and Guidance

FXHW60 PHFO 140614

Area Forecast Discussion
National Weather Service Honolulu HI
814 PM HST Mon Aug 13 2018

Moderate to breezy trade winds associated with high pressure to the
northeast will begin to weaken Tuesday through the second half of
the week. Dry and stable conditions are expected to remain in place
through midweek, which should keep the rainfall light. Lighter winds
along with increasing moisture expected by the end of the week into
the upcoming weekend may translate to increasing shower coverage
over the islands.


Short-term (through Tuesday night) guidance remains in decent
agreement and is initializing well with the current pattern and
trends. Consensus supports mostly stable and dry conditions with
moderate trades beginning to trend down in response to high pressure
weakening. The heavy showers and thunderstorms that managed to
develop over the leeward slopes of the Big Island this afternoon for
the second consecutive day have begun to diminish this evening. This
development was in response to a sufficient amount of heating,
moisture and the presence of a weak upper trough over the region.
Radar estimated peak accumulations ranging from 1-2 inches just up
the slope from Puuanahulu. The nearest gage reported a little over a
quarter of an inch in the past hour (Puu Waawaa). Although a
thunderstorm or two can't be ruled out again Tuesday afternoon,
forecast confidence remains too low at this point to include
thunderstorms in the official package. Elsewhere, benign conditions
are anticipated through Tuesday night with light to moderate trades.

The extended (Wednesday through the weekend) guidance remains in
decent agreement and supports light trades holding over the state,
likely allowing afternoon sea breezes to develop over leeward
locations. This combined with a large area of higher moisture
projected to approach and begin to fill in across the islands from
the east Friday into the weekend may lead to better shower coverage.
Lighter winds over the state will also support VOG becoming more
widespread over the Big Island and potentially spreading to the
smaller islands.


Trade winds will weaken a bit tomorrow and hold at light to
moderate speeds through much of the week. A fairly dry and stable
atmosphere will help keep VFR conditions across the islands
tonight and tomorrow. Any clouds and showers will favor windward
and mountain areas, with only very localized areas of MVFR
expected. No AIRMETS are expected through the period.


High pressure ridging north of the area will weaken as it drifts
south over the next few days, gradually weakening the trade winds
across the coastal waters. Light to moderate trades will then
prevail through the remainder of the week and over the upcoming
weekend as high pressure remains far northeast of the Hawaiian

The current south swell is expected to fade out through tonight,
and surf will remain small through rest of the week. Surf along
east facing shores will gradually decline as the trade winds
weaken. No significant swells are expected through the week.

See the latest Oahu Surf Discussion (SRDHFO) for more details on
surf and swell.






Bulletins, Forecasts and Observations are courtesy of Honolulu National Weather Service Forecast Office